Improved pitting corrosion behaviour of electrodeposited nanocrystalline Ni–Cu alloys in 3.0 wt.% NaCl solution

Abstract

Nanocrystalline (nc) Ni–Cu alloys have been electrodeposited by using pulse current (PC) as well as direct current (dc) electrolysis. X-ray diffraction (XRD) and transmission electron microscopy (TEM) were employed to characterise the deposits. High-resolution electron microscopic (HREM) examination revealed that deposited nc alloys were dense in nature. Corrosion behaviour of both nc as well as Monel-400 were compared in 3.0 wt.% NaCl solution and was found that corrosion current density (icorr) of nc alloys were superior to Monel-400. Both optical as well as scanning electron microscopic (SEM) examination of the corroded surface revealed a well-defined pitting type of attack for Monel-400 unlike nc alloys; akin to homogeneous corrosion.